Field of the Invention
The present invention generally relates to automatic detection of video artifacts.
Background Information
With the constant introduction of new features and cost reductions, reducing the time to market for new versions of set top boxes (STB) is critical to commercial success. Validation tests, such as stress tests, must be performed on the device to test its functions and stability. Validation tests consume a large portion of this time to market, so any reduction in the validation time will contribute to the commercial success of the product.
A stress test is one of the validation tests that are run over a long period of time, under different conditions such as temperature or humidity, in order to test the performance of the new STB. Since the tests are run over a long period of time, it is not practical for a developer to sit and watch the display in order to determine if a visible artifact has occurred with the picture. However, developers need to record those artifacts for debugging and product improvement.
Turning now to FIG. 1, two representations of an image comprising visible artifacts are shown 100. The right image 120 is the image having visual artifacts as displayed by the STB. The left image is the image edge map 110 depicting automatically detected visual artifacts according to a prior art method. Most of the visible artifacts shown in FIG. 110 are horizontal or vertical edges, so most of the existing methods detect the artifacts by checking the vertical/horizontal edges. However they only considered the direction and length of the edges, which results in many texture edges mistakenly identified as artificial edges. To reduce the number of false positives, they assume that the artificial edges exist at the boundaries of a macro block (MB) and only check the edges there. However this assumption is not true in some cases. For example, due to motion compensation or scaling, the position of the artificial edges may be not aligned with MB boundaries. It would therefore be desirable to have an automated process which can automatically detect out those frames and largely speed up the validation process while avoiding the above mentioned problems.